Long-term outcomes following en bloc resection for pancreatic ductal adenocarcinoma of the head with portomesenteric venous invasion

Background: The aim of this study is to clarify the prognostic influence of venous resection of the portal vein (PV) or superior mesenteric vein (SMV) on long-term outcomes in patients with pancreatic ductal adenocarcinoma (PDAC) of the head with suspected vascular invasion. Methods: From May 1995 to December 2014, a total of 557 patients underwent surgery with curative intent for pancreatic cancer of the head. Results: Among 557 patients, 106 (19%) underwent pancreaticoduodenectomy (PD) with PV-SMV resection and 89 (75.5%) of these patients were confirmed to have true pathological invasion. The 5-year overall survival rate in patients underwent PV-SMV resection was significantly lower compared with those who did not (18.7% versus 24.3%; p = 0.002). Patients with negative resection margins who underwent PV-SMV resection had a better prognosis than those with positive resection margins who did not undergo PV-SMV resection with positive resection margins (17% versus 6.3% in 5-year overall survival rate; p = 0.003). The overall morbidity rate was not significantly different between PV-SMV resection group and no PV-SMV resection group (p = 0.064). On multivariate analysis, margin status, advanced T stage (3 or 4), lymph node metastasis, and adjuvant therapy were independent prognostic factors for survival. Conclusion: PV-SMV resection was related to lower overall survival. However, on multivariate analysis, margin status was a more important prognostic factor than PV-SMV resection and true pathological invasion for survival. Therefore, en bloc PV-SMV resection should be performed when PV-SMV invasion is suspected to achieve R0 resection.